Refrigerating apparatus



H. F. CLARK Jan. 10, 1939.

REFR IGERAT ING APPARATUS Original Filed Jan. 30, 1934 5 Sheets-Sheet l TTORNEYS Jan. 10, 1939. H, p CLARK 2,143,620

REFRIGERATING APPARATUS Original Filed Jan. 30, 1934 5 Sheets-Sheet 2 ATTORNEY Jan. 10, 1939. H. CLARK 2,143,620

BEFRIGERATING AEPAHATUS Original Filed Jan 39, 1934 5 Sheets-Sheet 3 5 Sheets-Sheet 4 H. F. CLARK REFRIGERATTNG APPARATUQ Original Filed Jan. 30, 1934 Jan. 10, 1939.

H. F. CLARK Jan. 10, 1939.

REFRIGERATING APPARATUS Original Filed Jan. 30, 1954 5 Sheets-Sheet 5 a NiNTOi ATTORNEYS Patented Jan. 10, 1939v PATENT OFFICE nsrnrcnmrnvc APPARATUS Harry F. Clark, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application January 30, 1934, Serial No. 708,970 Renewed March 5, 1938 Claims.

This invention relates to refrigerating apparatus and more particularly to railway air conditioning equipment and protective devices for the electric motors therefor.

Recently the railroads of. the United States have begun to install air conditioning equipment upontheir passenger cars. The most common type of this equipment is the so-called battery system wherein a battery is provided which supplies electric current to the electric driving motor of the refrigerating system. This battery is replenished with electric energy by a generator driven by one of the axles on the car. However, it has been found that unless an excessively large generator is provided upon the car, the battery does not receive a sufiicient supply of energy during the running periods of the car to operate the refrigerating system at times when it is standing in the station, often for a considerable period of time.

In order to overcome this difficulty, the cars are supplied with an additional alternating current driving motor, ordinarily of the polyphase type, which operates the refrigerating system during the time the car or train is standing in the station or on a siding. In some installations the alternating current motor is also used to drive some suitable generating means at this time for replenishing the battery. In order to supply the alternating current to the alternating current motor, a plug type of receptacle is placed upon the car at a convenient point and various stopping points, particularly the different stations,

are provided with plug connectors connected by flexible electrical conductors to a polyphase source of alternating current. In such an installation, difficulty is encountered because of the fact that the phase sequence of the polyphase supply of electric energy is likely to be changed in making repairs to the electrical system which supplies the polyphase alternating current. Such a change in phase sequence may be caused by the accidental reversing of any two of the conductors of a three phase system and will cause the alternating current electric motor upon this car to rotate in the opposite direction from which it was intended to run. This is likely to damage the compressor and the generating means driven by the alternating current motor.

It is an object of my invention to provide a means for preventing the supply of polyphase alternating current of incorrect phase sequence to such a polyphase electric motor and in connection therewith to provide a means for indieating when the phase sequence is correct and when incorrect.

It is a further object of my invention to provide an automatic means for supplying electric energy of proper phase sequence to a polyphase 5 electric motor regardless of the phase sequence of the source of supply.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a diagrammatic view of a railway car and air conditioning system therefor provided with my improved motor protective device;

Fig. 2 is a fragmentary enlarged view of a portion of my motor protective device;

Fig. 3 is a front view of the protective device shown in Fig. 2;

Fig. 4 is a diagrammatic view of a railway car and air conditioning system therefor showing a modified form of my motor protective device;

Fig. 5 is a front view of the modified form of. motor protective device;

Fig. 6 is a sectional view along the line 6-6 of Fi 6;

Fig. '7 is a modification of the system shown in Fig. 4 wherein automatic reconnection for proper phase sequence is provided for the electric motor; and

Fig. 8 is a modified form of the system shown in Fig. 1 wherein automatic reconnection for proper phase sequence is provided for the alternating current motor.

Referring to the drawings, and more particularly to Fig. 1, there is shown diagrammatically a railway passenger car provided with an air conditioning system 2| comprising an evaporator 22 and fan means 23 for circulating air over the surfaces of the evaporator 22 and discharging the cooled air'into the interior 24 of the car 20. The evaporator 22 is supplied with liquid refrigerant by a refrigerant liquefying apparatus which includes a compressor 25 for compressing the refrigerant and forforwarding the compressed refrigerant to a condenser 26 where the condensed refrigerant is liquefied and collected in a receiver 21. From the receiver 21 the liquid refrigerant is forwarded through a supply conduit 28 under the control of an expansion valve 29 to the evaporator 22 where the liquid refrigerant evaporates under reduced pressure and is returned to the compressor through the return conduit 30.

The compressor 25 is driven by an electric motor 3| through a pulley and belt means 32. This motor preferably is a combined or dual drive alternating and direct current motor having in reality two motors, an alternating current motor and a direct current motor upon a single set of bearings. However, if desired, these motors may be made separate and provided with separate drives to the compressor. rent motor is preferably provided with field forcing means including a field forcing relay for enabling this motor to become a generator when driven by the alternating current motor. The direct-current electric motor is supplied with electric energy from a battery 33 at a suitable voltage, such as 32-38 volts. The electric energy from this battery is supplied to the direct current motor through the electric conductors 34 and 35 under the control of a relay 36.

The relay 36 is operated by electric energy supplied from a lamp regulator 31 which regulates the voltage of the current supplied by the battery. This lamp regulator is connected by an electrical conductor 39 to an alternating current relay 40 which controls the flow of electric energy from the lamp regulator 31 through a second electrical conductor 4| to a thermostat 42 located within the interior 24 of the car 26. The thermostat 42 is also connected by an electric conductor 43 through the relay 36 and the lamp regulator 31. When no alternating current is being supplied, the relay 40 is closed and the relay 36 is at that time under the control of the thermostat 42 which through the relay 36 controls the operation of the direct current motor and the refrigerating system to control the cooling of the interior 24 of the car.

Polyphase alternating current, preferably of three phase type, is supplied to the alternating current motor through the electrical conductors 44, 45, and 46. The supply of alternating current is controlled by an electromagnetic switch means or magnetic contactor 41 which has its circuit opening means in series with the electric conductors 44, 45, and 46. A plug type receptacle 48 is placed at a convenient point upon the side 01 the car to receive a plug connector 49 which is located at one of the stations upon the line and connected by flexible electric conductors 59, 5|, and 52 to a source of three phasev electric energy. The plug connector 49 is also provided with a jumper connection 53, which, when the plug 49 is inserted into the plug receptacle 48, is adapted to close the control circuit for alternating current operation providing the phase rotation or sequence is correct. This electric circult comprises the electromagnetic switch 41, the electrical conductor 4|, the thermostat 42, the electrical conductor 43, the relay 36, the lamp regulator 31, and the electrical conductors 54, 55, and 56 which connect the other side of the lamp regulator 31 to the plug jumper 53. In addition, this circuit is provided with one form of my motor protective device 51 which prevents the closing of the electromagnetic switch 41 when the phase rotation or sequence is improper.

This motor protective device 51 includes a polyphase electric motor supplied with electric energy from the electric conductors 50, 5|, and 52 through the electric conductors 58. The insertion of the plug 49 into the receptacle 46 energizes the relay 46 to open the direct current motor control circuit which includes the conductors 39, 4|, and thermostat 42, the conductor 1 43, the relay 36, and the lamp regulator 31. When The direct cur- .these conditions. energy of incorrect phase sequence is supplied to the supply of polyphase electric energy has the proper phase rotation or sequence, the motor pro-' tectlve device will then close the alternating current motor control circuit whichincludes the electromagnetic switch 41, the electric conductor 4|, the thermostat 42, the electric conductor 43, the relay 36, the lamp regulator 31, the conductors 54 and 55, the motor protective device 51, the conductor 56, and the plug jumper 53. This closes the electromagnetic switch 41 and causes the alternating motor to drive the compressor 25. At this time the field forcing means (not shown) causes the direct current motor to become a generator and to replenish the battery 33. However, if the supply of electric energy is of improper phase sequence, the motor protective device 51 will prevent the closing of the alternating current motor control circuit in order to protect the compressor and the direct current motor generator from incorrect rotation of the alternating current motor.

Referring now more particularly to Figs. 2 and 3 for a more detailed disclosure of the motor protective device 51, there is disclosed a polyphase electric motor 59, preferably of the three phase type, which is mounted upon a base 60. At the front of this base is provided a vertical plate 6| which is provided with a pivot pin 62 extending therefrom. This pivot pin 62 has a lever 63 pivotally mounted which is provided with spring clips 65 which carry a mercury tube type of switch means 64. This mercury tube type of switch means 64 is provided with an electrode 66 at its center portion and an electrode 61 at the end portion nearest the pivot pin 62. When the mercury tube type of switch means is in the position shown in Fig. 3, the pool of mercury 68 within the tube rests within the opposite end of the tube from electrode 61. When the tube is in this position the electric circuit is open. However, when the lever 63 is raised, the tube 64 is tilted in the opposite direction to cause the mercury within the tube to flow to the opposite end of the tube nearest the pivot pin 62. This causes the mercury 66 to wet both electrodes 66 and 61 to complete the alternating current motor control circuit.

The lever 63 is provided with bracket 69 extending therefrom which carries a cylindrical weight 19 which normally holds the lever 63 and the tube 64 in open circuit position. The lever 63 is also provided at its end portion with a sector gear 1| which meshes with the teeth of pinion 12 upon the shaft of the polyphase electric motor 59. The shaft of the polyphase electric motor 59 is also provided with a pin or arm 13 which projects therefrom and which is adapted to engage a stop pin 14 extending from the vertical plate 6|. When the electric motor 59 is deenergized the weight 19 will tend to "turn the lever 63 and the tube 64 in a clockwise direction about the pivot pin 62, as well as to turn the pinion 12 and the projecting arm 13 in a counterclockwise direction to a position against the pin 14 as shown in Figs. 2 and 3.

When polyphase electric energy of incorrect phase rotation is supplied, the polyphase motor 59 will tend to turn in a counterclockwise direction which will be prevented by the arm 13 and the pin 14. The motor 59 preferably has a sufficiently high resistance to prevent it from being damaged by being prevented from rotating under Thus, when polyphase electric the electric motor 59, the mercury tube switch means remains in the open position as shown in Fig. 3. However, when polyphase electric energy of correct phase sequence is supplied, the pinion I2 and the projecting arm 13 is rotated in a clockwise direction to raise the weight I and turn lever 63 and the mercury tube type switch means in a counterclockwise direction about the pivot pin 12 to close the alternating current electric motor circuit to permit operation of the polyphase compressor motor. By means of this simple device the generating means and the compressor are protected.

Referring to Fig. 4 in which a modified form of my invention is disclosed, there is again shown the railway passenger car 20 provided with a refrigerant air conditioning system 2| which is driven by dual drive compressor motor 3| comprising separate alternating current and direct current motors mounted upon the same shaft. When the train is in operation the electric motor 3| is supplied with direct current from the battery 80 under the control of a relay 8| through the electric conductors 82 and 83. operated by electric current from the lamp regulator 84 which is supplied with electric energy from the battery 80. The opening and closing of the relay 8! is controlled by a thermostat 85 located within the interior of the railway car 20' through an electric circuit forming the direct current motor control circuit which includes the electric conductors 86, 81, and 88 as well as the alternating current relay 89. When refrigeration is required by the air conditioning system, the thermostat 85 closes the direct current motor control circuit, thereby closing the relay 8| and the direct current motor circuit proper to cause operation of the electric motor and the refrigerating apparatus.

The motor 3| is also provided with the alternating current conductors 90, 9| and 92 for supplying polyphase alternating current thereto. In series with the conductors 90, 9|, and 92 is an electromagnetic switch means or magnetic contactor 93 which is connected to a plug type receptacle 94, preferably located at a convenient point upon the side of the car. The plug type receptacle 94 is adapted to receive plug connector 95 which is connected by the electrical conductors 98, 97, and 98 to a polyphase source of electric energy. The electrical plug 95 is also provided with a jumper connection 99 which forms a part of the alternating motor control circuit which controls the opening and closing of the electromagnetic switch 93. When the plug connector 95 is inserted into the plug receptacle 94, the alternating current relay 89 is energized by electric energy from the electrical conductors 96 and 91 to open the direct current motor control circuit.

The alternating current motor control circuit comprises the lamp regulator 84, the electric conductor 88, the thermostat 85, the electric conductor |0| leading to the plug jumper 99, the electrical conductor I02 connecting the plug jumper 99 with the motor protective device I00, the electrical conductor I03 connecting the motor protective device with the electromagnetic switch means 93 and the electrical conductor 81 which connects to the operating coil of the relay 8|.

This alternating current motor control circuit is provided with the motor protective device, generally designated by the reference character I00 which protects the motor 3| and the refrigerating system from operation in the wrong direction because of improper phase sequence of the supply The relay 8| is of polyphase electric energy. When the plug jumper 99 is inserted and alternating current of proper phase sequence is supplied, the motor protective device will close the alternating current motor control circuit and permit the alternating current motors to operate under the control of the thermostat 85. At the same time, the direct current motor, by suitable field forcing means, may be caused to become a generator and supply electric energy to replenish the battery 80. The relay 8| remains closed during the operation of the alternating current motor so as to permit the replenishing of the battery, but opens when the alternating current motor stops.

The motor protective device I00 is illustrated diagrammatically in Fig. 4 and comprises a multiple contact relay, or magnetic contactor I04, which is provided with a double winding operating coil having coils I and I06. The junction of these two coils, that is, the mid point of the entire coil, is connected by the electrical conductor I01. to the electrical conductor 91. The other end of the coil I05 is connected to the condenser I08 which in turn is connected by the electrical conductor I09 to the electrical conductor 91. The other end of the coil I06 is connected to a resistance or resistor III] which is connected by an electrical conductor III to the conductor 98.

The proper phase sequence in the conductors 96, 91, and 98 is designated by the letters A, B, and C in order to. designate the order in which the voltages increase to the maximum or line voltage. When the phase sequence or rotation is in the opposite direction, namely, C, B, A, the voltage cycle in the electrical conductor 98 leads the voltage cycle in the electrical conductor 96 by 120. By placing the resistance III] of the proper value in series with electrical conductor I I I, a lagging current is supplied to the coil H16. This current preferably lags behind the voltage about 20. The electrical conductor I09, on the other hand, has a condenser I08 in series therewith of sufficient capacity to supply the coil I05 with current which leads the voltage by about 90. This places the current in the coils I05 and I86 approximately in phase, or so nearly in phase, that practically no. magnetic attraction is exerted on the armature I04 and the armature I04 under these conditions remains in its open position wherein the contacts 2 are separated, thus preventing the operation of the electric motor 3| by the polyphase alternating current.

However, when the phase rotation or sequence is proper, as indicated by the letters A,-B, C, the voltage and current cycle in the conductor 96 will lead the voltage and current cycle in the conductor 98 by approximately 120. The condenser I08 which is connected to the conductor 96 by the conductor I09 will cause the current in the coil I05 to lead the voltage in the conductor 98 by approximately 90. While the resistance H0 which is connected to the conductor 98 by zhe conductor III will cause the current in the coil I06 to lag behind the voltage by about 20, in addition to the fact that the voltage and current cycle in the conductor 98 lags behind the voltage and current cycle in the conductor 36 by about 120. This causes the current in the coils I05 and I06 to be more than 186 apart (230) but since the coils Hit and INS oppose each other, the currents in these coils I05 and H38 are thrown so nearly in phase that a strong magnetic attraction results upon the armature I04, causing the closing of the fjoll'ilactf II2, and permitting the alternating current electric motor control circuit to close.

In order to indicate when alternating current of the proper phase sequence is being supplied to the car, there is provided a second set of contacts II3 to be opened and closed by the relay I04 which contacts control the lighting of an indicating lamp 4 which with the contacts H3 is connected in a shunt circuit II5 connecting the conductors III and I09. Thus when the relay I04 is closed, current is supplied to the indicating lamp II4 for indicating when polyphase electric current of the proper phase sequence or rotation is being supplied to the electric motor 3|.

Referring now to Figs. 5 and 6 for the more complete illustration of this form of motor protective device, there is shown a sheet metal box I20 having a lid I2I hinged at I22 to the top of the box. This box is provided with mounting studs or bolts I23 which extend from the rear of the box and which support an insulating panel I24. At the top of the box and supported upon the insulating panel I 24 by the spacers and screws I25 is an insulating terminal bar I26 which is provided with the binding posts I21, I28, and I29, and I30. The binding post I21 is connected by an electrical conductor I3I which extends beneath the panel I24 to a bindingpost I32 which connects to the midpoint of a relay coil I33 which includes the coils I05 and I06. The portion of the coil I33 which includes the coil I06 is connected by the electrical conductor I34 which extends beneath the panel to the binding post I30 which in turn is connected by the conductor I35 to the resistor or resistance H0. The resistor H0 is in turn connected by electrical conductor I36 to the binding post I29 which is connected to the conductor III. The binding post I29 is also connected by an electrical conductor I31 which extends beneath the panel I24 to the set of switch contacts I I3 which are connected to an insulating cross arm I38 connected to the relay armature I04. The contacts II3 are also connected by an electrical conductor I39 to a binding post I40 which connects to the indicating lamp H4. The indicating lamp H4 is connected by an electrical conductor I 4| to a condenser or capacitor I08 which in turn is connected by the electrical conductor I42 to the portion of the relay coil I33 which corresponds to the coil I05. The lamp I I4 is also connected by an electrical conductor I43 which extends beneath the panel I24 to the binding post I28 which connects to the electrical conductor I09. This insulating cross arm I38 also carries the set of contacts H2 at the end opposite the contacts II3 to open and close the alternating current motor control circuit.

Referring now more particularly to Fig. 7, there is shown a control system which embodies a form of my motor protective device wherein the electrical circuits are automatically reconnected to supply polyphase current to the motor 3I having the proper phase rotation or sequence, regardless of the phase rotation or sequence of the source of supply. In this form the dual drive compressor motor is again indicated by the reference character 3| and the air conditioning system is again indicated by the reference character 2|. The direct current motor forming'part of the dual motor 3I is supplied with electric energy from the battery I50 when the train is in operation through the electric conductors i5! and I 52 under the control of an alternating current relay I53. In order to simplify the diagram, the direct ourrent motor control circuit including the thermostat has,been omitted, but the operation when the train is in operation is similar.

The alternating current motor forming part of the dual motor 3| is connected by the electrical conductors I54, I55, and I56 to the electromagnetic switch or alternating current magnetic starter I51. This electromagnetic switch or starter is connected through a two pole double throw magnetic reverser I58 which includes the contacts I59 I and I60 connected in parallel through the electromagnetic switch I51 to the electrical conductor I54 and the contacts I6I and I 62 which are connected in parallel to the electromagnetic switch I51 to the electrical conductor I56. The electrical conductor I55 through the electromagnetic switch I51 is connected directly by the electrical conductor I63 to the electrical conductor I64 which forms the middle terminal of the plug receptacle I65.

The contacts I59 and I6I are adapted to be engaged by the double throw magnetic reverser 'I66 which is connected through the conductor I61 to the conductor I68 connected to one of the end terminals of the plug receptacle I65. Thecontacts I60 and I62 are adapted to be engaged by a double throw magnetic reverser I69 which is in turn connected by the electrical conductor I10 to the terminal at the opposite end of the plug receptacle I5I.

I66 and I69 are connected to a common operating rod I1I which is resiliently pulled upwardly by a tension spring I12. At the lower end of the rod I1I there is provided an electromagnetic coil I13 which is adapted to be energized when the relay 204 of a motor protective device 200 is closed.

This motor protective device is identical to the motor protective device I00 as shown in Figs. 4, 5', and 6. This motor protective device 200 has the relay contacts 2I2 connected to the electrical conductor I64 and through the electrical conductor I14 to the electromagnet I13. The electromagnet I13 is also connected by the electrical conductor I15 to the condenser 208 and the lamp 2I4 of the motor protective device 200 and by the electrical conductor I16 to the conductor I 10. The indicating contacts 2 I3 forming a part of the relay 204 control the indicating light 2I4 and are also connected to the resistance 2I0 and the conductor I68. The relay operating coils 205 and 206 have their opposite end portions connected to the condenser 208and restrictor 2I0 respectively while their common connecting point is connected to the conductor I64.

When electric energy of the proper phase sequence or rotation A, B, and C is supplied by the plug I11 to receptacle I65, the relay coil 204 will remain deenergized so that the tension coil spring I12 will hold the magnetic reverser rod Ill in its upper position in which the conductor I68 is connected by conductor I61, the double throw reverser switch I 66, the contact I59, the electromagnetic switch I51, to the conductor I54. In this position the conductor I10 is connected through the double throw switch I69, the contact I62, and the electromagnetic switch I51 to the electrical conductor I56, while the electrical conductor I63 is connected through the switch I51 to the conductor I55. When electric energy of improper phase sequence or rotation, namely C, B, A, is supplied, the relay 204 closes, thus lighting lamp The double throw reversers 2I4 and energizing the electromagnet I13 which pulls the magnetic reverser rod I1I downwardly to engage the contacts IN and I60 respectively.

- ing system as 2|.

This reverses the connection between the receptacle I65 and the electrical conductors I54 and I56 so that electric energy of the proper phase sequence is supplied to the electric motor 3| even under these conditions. Under these conditions, the electric energy is conducted from the conductor I68 through the conductor I61, the double throw switch I66, the contact I6I, through the conductor I56, while electric energy from the conductor I10 is conducted by the double throw switch I68 through the contact I60 which in turn is connected through the electromagnetic switch I51 to the conductor I54. In this automatic form, the indicating light may be dispensed with.

In order to protect the motor 3| from the current of improper phase sequence which might flow through the reverser when in the position shown in Fig. '7 before the reverser had an opportunity to reverse the flow of current to the motor 3I, I have provided a time delay device I80 comprising a wire heater coil I8I and a bimetal strip I82 which is adapted to close the contacts I83 only after a certain amount of heat corresponding to a predetermined flow of electric energy through the heater I8I has caused suflicient heat to be. generated to cause the bimetal strip I82 to bow upwardly to close the contacts I83. These contacts I83 are connected in series with the control circuit I84 of the electromagnetic switch I51 which is connected to the battery I50. This heater I8! is connected to the contact I59 and to the conductor I63 so that when the plug I11 is inserted into the receptacle I65 the electromagnetic switch I51 will not close until after a predetermined length of time corresponding to the predetermined heating of the bimetal strip which insures that a suflicient length of time is provided to permit the double I pole double throw magnetic reverser I58 a sufiicient time to operate if necessary before the closing of the electromagnetic switch I 51. The operating coil of the relay I53 is also connected to the contacts I59, I60, and the electrical conductor I 63 so-that if desired the relay I63 will open the direct current motor circuit during the operation of the alternating current motor when it is not desired to use the direct current motor as a generator. If it is desired to use the direct current motor as a generator, this relay I53 is replaced by a field forcing relay and field forcing means to cause the direct current motor to become a generator during the operation of the alternating current motor.

In Fig. 8 another automatic form is disclosed which is somewhat similar to the forms shown in Figs. 1 to 3. In this figure the duel drive motor is again designated as 3| and the air condition- In this figure the battery 230 is employed for supplying direct current through the conductors 23I and 232 under the control of a relay 233 to the direct current motor portion of the motor 3|. The relay 233 is of the gravity type and when deenergized completes the circuit to the direct current motor. The motor 3I is also provided with the polyphase electric conductors 234, 235, and 236 which connect to the electromagnetic switch or magnetic starter 231 which is controlled by the alternating current motor control circuit including the conductors 238 and 239 as well as the relay contacts 240.

A plug receptacle 24I is provided at a convenient point upon a side of the car and is adapted to receive a plug connector 242 which in this figure is shown disconnected. This plug connector 242 is connected by flexible electric conductor to a polyphase source of alternating current. The plug receptacle 24I is connected by the electric conductors 243, 244, and 245 to a small high resistance polyphase pilot motor 245 which is provided with a sector gear 241 provided with a heavy over-balancing counterweight 248 which remains in a downward position when the motor 246 is deenergized. When the motor 246 is energized by electric current of the proper phase rotation or sequence, it will tend to turn in a clockwise direction and more to a position in which the sector gear 241 comes into contact with a stop pin 249. If the phase rotation or phase sequence is reversed or improper, the motor 246 will turn the sector gear 241 in a counterclockwise direction against a second stop pin 250.

The sector gear 241 meshes with a rack formed upon a reversing bar 25I which is connected to operate the double throw switches 252 and 253. The electric conductor 246 is connected by the conductor 254 to the double throw switch 253 while the electric conductor 243 is connected by the conductor 255 to the double throw switch 252. When the phase rotation is in the proper direction, as stated before, the sector gear will rotate in a clockwise direction and this will cause a double throw switch 252 to engage the contact 256 which is connected by the electrical conductor 251 through the electromagnetic switch 231 to the electric conductor 236. This clockwise movement of a sector gear 241 will also cause the double throw switch 253 to engage the contact 258 which connects through the conductor 259 and the electromagnetic switch 231 to the conductor 234. The conductor 244 is connected by the electrical conductor 260 directly to the middle portion of the electromagnetic switch 231 which connects to an electric conductor 235. The closing of the double throw switch 252 and 253 energizes the relay coil 26I which closes the alternating current motor control circuit by closing the relay contacts 240. This closes the electromagnetic switch 231 and causes the motor 3| to operate in a proper direction by polyphase alternating current.

When the plug receptacle 24I is supplied with polyphase alternating current of improper phase sequence or rotation by the plug connector 242, the motor 240 will turn the sector gear 241 in a counterclockwise direction to cause the double throw switches 252 and 253 to engage the contacts 262 and 263 respectively. This, as before, causes the energization of the relay coil 26I to close the relay contacts 240 but reverses the connection of the conductors 243 and 245 with the electric conductors 234 and 236, while the conductor 260 remains connected as before with the conductor 235.

By the use of this simple device the proper electrical connections to supply polyphase alternating current of the proper phase sequence or rotation to the motor 3| is insured.

By these different forms of device I have provided means whereby the electric motor 3I and particularly the direct current motor portion is protected from a supply of polyphase alternating current of incorrect phasesequence. This also protects the compressor of I the refrigerant air conditioning system. While the three phase system has been used to illustrate the invention, the invention is also applicable to the two phase system and in such a system the electrical connections of the protective device which are shown connected to the middle conductor of the three phase system are in the two phase system connected'to the additional or return conductors of the two phase system.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What. is claimed is as follows:

1. A control system including apparatus capable of being properly operated by polyphase electric current of a certain phase sequence or by direct current optionally as desired, battery means for supplying direct current, a plug receptacle for receiving polyphase electric current, a polyphase electrical conducting system for conducting polyphase electric current from said plug receptacle to said apparatus; an electrically operated switch means connected into said polyphase electrical conducting system in series with the plug receptacle and said apparatus, for controlling the polyphase energization of said apparatus; a direct current control circuit supplied with electric current from said battery means, said electrically operated switch means having its operating means supplied with electric energy by said control circuit, a switch means in the control circuit in series with said operating means closed by the insertion of the plug into the receptacle, said control circuit also having a phase controlled switch means in series with said operating means movable to closed positionwhenpolyphase electric current of the correct phase sequence is supplied to the plug receptacle and movable to open position when such current is not supplied, said phase controlled switch means being controlled by electric current supplied to the plug receptacle, said battery means being also connected to said device, said connection including a direct current apparatus controlling switch means.

2. A control system including apparatus capable of being properly operated by polyphase electric current of a certain phase sequence or by direct current optionally as desired, battery means for supplying direct current, a plugreceptacle for receiving polyphase electric current, a polyphase electrical conducting system for conducting polyphase electric current from said plug receptacle to said apparatus, an electrically operated switch means connected into said polyphase electrical conducting system in series with the plug receptacle and said apparatus for controlling the polyphase energization of said apparatus, a direct current control circuit supplied with electric current from said battery means, said electrically operated switch means having its operating means supplied with electric energy by said control circuit, a switch means in the control circuit in series with said operating means closed by the insertion of the plug into the receptacle, said control circuit also having a phase controlled switch means in series with said operating means movable to closed position when polyphase electric current of the correct phase sequence is supplied to the plug receptacle and movable to openposition when such current is not supplied, said phase controlled switch means being controlled by electric current supplied to the plug receptacle, said battery means being also connected to said device, said connection including a direct current apparatus controlling switch means, a shunt in said control circuit around said operating means and said plug and said phase controlled. switch means, a

switch means in said shunt movable to open position when electric current is supplied to the plug receptacle and movable to closed position when no electric current is supplied to the plug receptacle.

3. A control system including apparatus capable of being properly operated by polyphase electric current of a certain phase sequence or by direct current .optionally as desired, battery means for supplying direct current, a plug receptacle for receiving polyphase electric current, a polyphase electrical conducting system for conducting polyphase electric current from said plug receptacle to said apparatus, an electrically operated switch means connected into said polyphase electrical conducting system in series with the plug receptacle and said apparatus for controlling the polyphase energization of said apparatus, a direct current control circuit supplied with electric current from said battery means, said electrically operated switch means having its operating means supplied with electric energy by said control circuit, a switch means in the control circuit in series with said operating means closed by the insertion of the plug into the receptacle, said control circuit also having a phase controlled switch means in series with said operating means movable to closed position when polyphase electric current of the correct phase sequence is supplied to the plug receptacle and movable to open position when such current is not supplied, said phase controlled switch means being controlled by electric current supplied to the plug receptacle, said battery means being also connected to said device, said connection including a direct current apparatus controlling switch means, a shunt in said control circuit around said operating means and said plug and said phase controlled switch means, a switch means in said shunt movable to open position when electric current is supplied to the plug receptacle and movable to closed position when no electric current is supplied to the plug receptacle, said control circuit including a control switch in series with both said shunt and said operating means, and a second electric operating means for said apparatus controlling switch means, said second electric operating means being connected in series with said control switch.

4. A control system including apparatus capable of being properly operated by power derived from a polyphase electric current source of a certain phase sequence or by power derived from a direct current source optionally as desired, an electric current receptacle for receiving polyphase electric current, a polyphase electrical conducting system for conducting polyphase electric current from said current receptacle to said apparatus; an electrically operated switch means connected into said polyphase electrical conducting system for controlling the polyphase energization of said apparatus; battery means for supplying direct current, a direct current control circuit supplied with electric current from said battery means, said electrically operated switch means having its operating means supplied with electric energy by said control circuit, saidcontrol circuit also being provided with phase controlled switch means controlled by polyphase current supplied to the current receptacle for operatively connecting said operating means to the control circuit when polyphase electric current of the correct phase sequence is supplied to the current receptacle and for prevent- 7 ing the operative connection oi said operating means with the control circuit when such current is not supplied, said battery means being also electrically connected to said apparatus for supplying said apparatus with direct current electric energy.

5. A control system including apparatus capable of being properly operated by power derived from a polyphase electric current source of a certain phase sequence or by power derived from a direct current source optionally as desired, an

electric current receptacle for receiving polyphese electric curren, a polyphase electrical conducting system for conducting polyphase electric'current from said current receptacle to said apparatus; an electrically operated switch means connected into said polyphase electrical conducting system for controlling the polyphase energization'of said apparatus; battery means for supplying direct current, a direct current control circuit supplied with electric current from said battery means, said electrically operated switch means having its operating means supplied with electric energy by said control circuit, said control circuit also having a phase controlled switch means controlled by the energization of the polyphase circuit and connected in series with said operating means and being movable to closed position when polyphase electric current of the correct phase sequence is supplied to the current receptacle and being movable to open position when such current is not supplied, a shunt in said control circuit around said operating means and said phase controlled switch means, a switch means in said shunt energizecl by electric current supplied to said current receptacle and movable to open position when electric current is supplied to said current receptacle to open said shunt and movable to closed position to permit the flow of electric current through said shunt when no electric current is supplied said battery means being also electrically connected to said apparatus for supplying direct current to said apparatus.

HARRY F. CLARK. 

